Brown fuzzy algae

[lee3]

I'm struggling with this algae, which I'm having trouble even finding out what it is, let alone getting rid of it.


Brown fuzzy coating - tends to lower areas on some ?Lindernia, but I note similar on older leaves of some Hygrophila, and less so on Java Fern.


Tank set up for 6 months.


130L, temp 26-27 deg, GH 5.6


CO2 - pressurized, pH controller, pH drops from 7.72 in am to 6.60 through entire photoperiod, KH 3


Lights - LED, 2 strips of 12x3W (max power 1.5W each) - total period 10h, 2h sunrise/sunset, 6h 70% (plus 2hr @ 100%)


ferts - KNO3 to keep NO3 minimum 10ppm, KH2PO4 keep PO4 2-2.5ppm


water changes - 50% per week, add KHCO3 to boost KH to 3, add Seachem Equil to raise GH by 1.


micros - daily according to EI, use 'Amgrow chelated micronutrients' and approx 0.5mL Seachem Fe gluconate daily


(until this week I was doing 2x50% per week)


the pics show what I mean - the worst is on the lower zones of what I think is Lindernia (I think sold as pennywort). Some on older Hygrophila polysperma leaves, less so on Hygrophila leaves only 1-2weeks old.


I don't think this is diatoms - I had a major bloom of them at week 3-4 or so, which resolved, and this stuff doesn't come off like diatoms do.


I noted a thread elsewhere, where this stuff was thought to be a cyanobacteria. I am stumped.


Plants are growing rapidly, pearling nicely.


I'm starting to realise maybe I haven't been trimming properly, and the base of the pennywort is pretty old - probably 6 months.... I am planning to top it off, and probably bleach it....


Any thoughts??

 

[lee3]

hopefully pics will be visible now...


My wife works as a scientist in clinical microbiology - this brown matter under the microscope is rafts/chains of gram negative bacterial cells..... cyanobacteria.... should get a microscopy image later in the week, will post it when available.


To be honest I think it is already on the back foot - I added a circulation pump a week ago to blow more water into the corner where this stuff mostly is, it doesn't seem as thick now. I am planning on pulling this stuff up, and replanting the tops after probably giving them a good soak in something - I have the usual Excel/glut/H2O2/bleach, and can access any antibiotic - any suggestions?

 

[Apprentice]

Hi Lee, Can see the photos fine now.


Cyanobacteria can result for a few different reasons. Low nitrates causing plants not to do well and releasing organics back into the tank. Low oxygen (High temps and/or poor water circulation) levels also leading to nitrogenous organic build up. Dirty substrate and or dirty filter. Overall causes either poor plant health and/or lack of maintenance.


You can use erythromycin to eradicate cyanobacteria. In your case since it seems to be only a thin layer on plants leaves and not whole tank, I would stick with your original plan of topping and replanting. Maybe dip effected plants in a dip of 5:1 ration of water and H2O2 for 5 minutes. A bit less harsh then bleach and you won't need to dechlorinate after.


In my case in the past cyanobacteria was usually caused by high temps. (AKA summer heat waves and no AC) and insufficient nutrients to keep up with accelerated growth rates.


In your case I think your on the right track. Increased flow to get nutrients and co2 to back corner of tank.


Regards, Rob

 

[lee3]

From memory what happened was the diatom bloom came and went, then maybe in January/February, in the heat of summer, this got going - I tend to use the aircon if the tank temp is rising through 28.5 deg C (83 deg F) and the day is hot. Nutrients have always been pretty good, nitrates are never under 7.5ppm, generally 10-15ppm. The tank has an overhead trickle filter, and I've done minimum 50% water changes per week (twice weekly for the last 2 months). I had gotten pretty stingey with the micronutrients though, was down to under 1/3 or EI, and with two water changes..... I have picked this up now.


I'm not keen to treat the tank at this stage, may treat the plants in a bucket with erythromycin though, might double whammy them with H2O2 after!


Thanks for your reply Rob....

 

[lee3]

Cyano - top images above on Lindernia - Wet prep microscopy, no stains, just scraped and put under a cover-slip.




View attachment 10189

 

[lee3]

Microscopy of brown coating on Hygrophila - diatoms.....




View attachment 10190

 

[Apprentice]

Pretty cool. Didn't realize cyanobacteria was long strands.


I know from previous posts Tom Barr has made states that our tanks almost always have some cyano and diatoms in them. Just when things are in balance they don't accumulate enough to be an issue.


How is your tank doing now? Made any other changes? Let us know.


Regards, Rob